Not long ago, genetic tests that are widely available today were the domain of dystopian science fiction. Now, they're a nice gift to buy your genealogy-minded aunt for her birthday. Companies such as 23andMe, Ancestry.com and National Geographic market these at-home DNA testing kits, offering to unlock your genetic secrets for the price of a group dinner at a nice restaurant and about half a teaspoon of spit. And although there was a time when these tests were marketed primarily as health services — ways to test for diseases and better understand your body — that aspect of their branding has partly receded, in part thanks to action from U.S. regulators. Nowadays, most of the big genetic testing companies pitch themselves primarily as "ancestry" services, promising both to connect long-lost relatives and to tell users what parts of the world their ancestors came from. Buy 23andMe on Amazon.com BUY Ancestry.com Test Kit >>> Buy Nat Geo DNA Test Kit on … [Read more...] about How Do DNA Ancestry Tests Really Work?
How are dna and chromosomes related
When you think of DNA, odds are, you picture the famous double helix, a ladder-like structure elegantly twisted like a corkscrew. But DNA doesn't always assume this form. The existence of one shape of DNA in humans, in particular — a four-stranded knot of genetic code — has been controversial among scientists for years. Because this so-called i-motif loves acidic environments (a condition that scientists can create in the lab but doesn't naturally occur in the body), many scientists thought that it couldn't possibly exist in human cells. But in recent years, studies have pointed to the possibility that this bizarre form of DNA could, in fact, exist in living humans. Now, a new study published today (April 23) in the journal Nature Chemistry provides the first direct evidence that it does exist and that it may play an important role in regulating our genes. [Unraveling the Human Genome: 6 Molecular Milestones] "Before this, it was kind of an academic idea that DNA could … [Read more...] about A Mysterious New Form of DNA Was Just Discovered in Human Cells
If a flurry of news coverage is to be believed, a year in space can really wreak havoc on your DNA. According to some press reports this week, NASA astronaut Scott Kelly's DNA changed by 7 percent because of the year he spent living above the planet on the International Space Station. Kelly himself even tweeted about the idea that he's no longer identical twins with his brother and fellow astronaut Mark Kelly. But that's not the full story. SEE ALSO: First Astronaut on Yearlong ISS Mission Reveals Commemorative Patch Kelly's base DNA didn't actually change by 7 percent during his time in space. His gene expression — the transcribing and translation of genes, not the genes themselves — was what actually changed during his year on the Space Station. According to NASA, 93 percent of Kelly's gene expression went back to "normal" after he returned to Earth in March 2016, but it seems that about 7 percent may have been altered more permanently. … [Read more...] about Scott Kelly’s DNA changed in space, but that doesn’t mean what you think it means
Nature: 1, nurture: 0. After spending nearly a year aboard the International Space Station, American astronaut Scott Kelly returned to Earth in 2016—only to find that his DNA had changed. One half of the NASA Twins Study examining the effects of long-term space flight on the human body, Scott orbited our planet for 340 days, while his identical twin brother, Mark, stayed home. Following a triumphant homecoming, Scott, still readapting to Earth’s gravity, became a NASA lab rat, completing tests to determine changes in his pre- and post-flight status. Most biological fluctuations quickly reached baseline; some took hours or days, while a few persisted after six months. Unlike Japanese astronaut Norishige Kanai, who claimed to have grown 9 cm (3.5 inches) during his trip to the cosmos, Kelly came home an impressive 2 inches taller than his twin. “Scott’s telomeres (endcaps of chromosomes that shorten as one ages) actually became significantly longer in … [Read more...] about Astronaut Scott Kelly’s DNA Changed in Space
A human cell carries in its nucleus two meters of spiraling DNA, split up among the 46 slender, double-helical molecules that are its chromosomes. Most of the time, that DNA looks like a tangled ball of yarn—diffuse, disordered, chaotic. But that messiness poses a problem during mitosis, when the cell has to make a copy of its genetic material and divide in two. In preparation, it tidies up by packing the DNA into dense, sausagelike rods, the chromosomes’ most familiar form. Scientists have watched that process through a microscope for decades: The DNA condenses and organizes into discrete units that gradually shorten and widen. But how the genome gets folded inside that structure—it’s clear that it doesn’t simply contract—has remained a mystery. “It’s really at the heart of genetics,” said Job Dekker, a biochemist at the University of Massachusetts Medical School, “a fundamental aspect of heredity that’s always been … [Read more...] about How Cells Pack Tangled DNA Into Neat Chromosomes
We can understand the prehistoric past only by interpreting the things people left behind. Finds don't come with words to explain how an object arrived at a site or why people decorated a pot a certain way. So there’s a lot of detail about prehistoric people’s lives, cultures, and interactions that these objects can only hint at. In recent years, however, the DNA of ancient people has added depth and detail to the information gleaned from artifacts. Genomic studies, it turns out, can tell us who the people using those artifacts were and where they came from. Most of the genomic work so far has been relatively small-scale due to the massive effort involved in sampling and processing ancient DNA, but two new studies add several hundred prehistoric genomes to the existing data. “The two studies published this week approximately double the size of the entire ancient DNA literature and are similar in their sample sizes to population genetic studies of people living … [Read more...] about Prehistoric Europe much like a game of Civilization, according to ancient DNA
It's possible to infer many species' origins from things like fossils and DNA sequences. But for one creature, we have a specific date: 1995. That's when the first marbled crayfish appeared in a pet shop in Germany, mixed in with similar-looking animals that had originally come from streams in the US South. When it came to selling pets, the marbled crayfish had a big advantage over its relatives: it doesn't need males to reproduce. Instead, females are able to produce genetic copies of themselves, allowing any fish tank to become a factory for an army of crayfish clones. Now, researchers have confirmed that these clones have spread throughout Europe, gotten as far as Japan, and begun invading the streams of Madagascar. Ostensibly, the publication that describes these results is about the completion of the genome for the marbled crayfish. And the genome is what has allowed researchers to confirm that crayfish from around the world are essentially clones. But the real story in Nature … [Read more...] about Mutant crayfish got rid of males, and its clones are taking over the world
DNA test kits like AncestryDNA and 23andMe have become increasingly popular over the past few years and were a surprisingly popular gift item during the holiday season. Though DNA tests are being added to more and more people's bucket lists, the sheer number of kits you can choose from is overwhelming. The result? A lot of interested folks opt out simply because they're not sure which kit to buy. And that sucks, because finding out the whos, whats, and wheres that made you into the person you are is way too awesome to pass up. We did some digging to bring you the ultimate DNA test comparison guide. We've looked at five of the most popular DNA test kits out there: AncestryDNA,23andMe,MyHeritage,Living DNA, andFamily Tree DNA to give you the rundown on the differences between each kit so you can decide which one is the best for you. SEE ALSO: Which robot vacuum should you get? This list can help you figure it out. Before we get into the nitty-gritty of each kit, it's … [Read more...] about Which DNA test should you get? This guide can help.
Some human tissues, like the liver and muscles, retain the ability to regrow after damage. But most of our bodies do not—if you lose a limb, the limb's gone. But elsewhere in the animal kingdom, regeneration is much more widespread. Many reptiles can regrow tails, and some salamanders can replace entire limbs. More distantly related worms called planaria can be cut into multiple pieces and see each piece regrow an entirely new body. There are a couple of organisms that have been extensively studied due to their ability to regenerate: the planarian Schmidtea mediterranea and a type of salamander called an axolotl (Ambystoma mexicanum). But those studies have been limited by the fact that we don't have a complete catalog of genes for these organisms. Attempts to correct that were bogged down by the fact that the genomes appeared to be littered with duplicate copies of virus-like DNA—in the case of the axolotl, enough to balloon its genome up to 10 times the size of our own. … [Read more...] about A salamander with a genome 10 times the size of ours regrows lost limbs
Our genes shape the way we look and how our bodies work, and looking at specific genes or snippets of DNA can offer scientists a glimpse of the control panels for many different physical traits. But researchers are still piecing together the relationship between genes and behavior, and indeed, little is known about how certain types of genes can influence human psychology. Recently, a rare disorder known as Prader-Willi syndrome (PWS) gave scientists an unprecedented opportunity to pinpoint the location of certain genetic activity associated with paranoia, a mental condition that frequently occurs in people with PWS. Many traits found in people with PWS — including paranoia — are associated with anomalies in two genes on a single chromosome. In a new study, scientists investigated the genetic makeup of people with the syndrome, noting which individuals exhibited more signs of paranoid behavior and looking for patterns in gene expression, which is the activation of … [Read more...] about Gene Location for Paranoia Found